A word to use with caution is the word “but”! Most people are not aware that this word negates everything in front of it… So when you say ;
Good job, but next time…
The result will be that the good part is not remembered. Doing it the way around will then have the opposite effect.
Luckily enough, there are simple ways to avoid this trap. You can use the words “yet”, “however” or “and” as replacements. These words do not have this negative effect, which will result in your message being passee more effectively.